< draft-nilsson-audio-mpeg-02.txt		draft-nilsson-audio-mpeg-03.txt >
	Internet Engineering Task Force M. Nilsson		Internet Engineering Task Force M. Nilsson
	INTERNET DRAFT 26 April 2000		INTERNET DRAFT 27 August 2000
	Document: draft-nilsson-audio-mpeg-02.txt		Document: draft-nilsson-audio-mpeg-03.txt
	Expires 26 October 2000		Expires 27 February 2001
	The audio/mpeg Media Type		The audio/mpeg Media Type
	Status of this Memo		Status of this Memo
	This document is an Internet-Draft and is in full conformance with		This document is an Internet-Draft and is in full conformance with
	all provisions of Section 10 of RFC2026.		all provisions of Section 10 of RFC2026.
	Internet-Drafts are working documents of the Internet Engineering		Internet-Drafts are working documents of the Internet Engineering
	Task Force (IETF), its areas, and its working groups. Note that		Task Force (IETF), its areas, and its working groups. Note that
	skipping to change at page 1, line 38 ¶		skipping to change at page 1, line 38 ¶
	The list of Internet-Draft Shadow Directories can be accessed at		The list of Internet-Draft Shadow Directories can be accessed at
	http://www.ietf.org/shadow.html.		http://www.ietf.org/shadow.html.
	Abstract		Abstract
	The audio layers of the MPEG-1 and MPEG-2 standards are in frequent		The audio layers of the MPEG-1 and MPEG-2 standards are in frequent
	use on the internet, but there is no uniform MIME type for these		use on the internet, but there is no uniform MIME type for these
	files. The intention of this draft is to define the media type		files. The intention of this draft is to define the media type
	audio/mpeg to refer to this kind of contents.		audio/mpeg to refer to this kind of contents.
			The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
			"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
			document are to be interpreted as described in RFC 2119 [RFC2119].
	1. MPEG audio		1. MPEG audio
	The audio compression defined as layer I, layer II and layer III in		The audio compression defined as layer I, layer II and layer III in
	the MPEG-1 [MPEG-1] and MPEG-2 [MPEG-2] standards is a popular method		the MPEG-1 [MPEG-1] and MPEG-2 [MPEG-2] standards is a popular method
	of compressing audio with a low quality loss. The compressed audio is		of compressing audio with a low quality loss. The compressed audio is
	split into several small data frames, each containing a frame header		split into several small data frames, each containing a frame header
	and compressed audio data.		and compressed audio data.
	The mime type audio/mpeg defines a elementary byte stream containing		The mime type audio/mpeg defines a elementary byte stream containing
	MPEG frames according to [MPEG-1] and [MPEG-2], possibly interspersed		MPEG frames according to [MPEG-1] and [MPEG-2], possibly interspersed
	with non MPEG data. Non MPEG data is data without MPEG		with non MPEG data. Non MPEG data is data without MPEG
	synchronisation or in other ways not possible to decompress without		synchronisation or in other ways not possible to decompress without
	error.		error.
			Internet DRAFT The audio/mpeg Media Type August 2000
	Typically MPEG audio meta data is concatenated with the MPEG stream,		Typically MPEG audio meta data is concatenated with the MPEG stream,
	e.g. the meta data format ID3 puts a 128 byte data block in the end		e.g. the meta data format ID3 puts a 128 byte data block in the end
	of the stream while ID3v2 [ID3V2] prepends a data block of variable		of the stream while ID3v2 [ID3V2] prepends a data block of variable
	size to the stream.		size to the stream.
	NOTE: MPEG audio was not designed as a file format but as a format		NOTE: MPEG audio was not designed as a file format but as a format
	for transmitting audio streams. As such, it does not have any		for transmitting audio streams. As such, it does not have any
	well defined way of including meta data along with audio information.		well defined way of including meta data along with audio information.
	Some products embed meta data using zero amplitude frames or		Some products embed meta data using zero amplitude frames or
	disguised as transmission errors. Others embed the MPEG data in WAV		disguised as transmission errors. Others embed the MPEG data in WAV
	skipping to change at page 2, line 44 ¶		skipping to change at page 2, line 46 ¶
	frames generated without the optional cyclic redundancy checks		frames generated without the optional cyclic redundancy checks
	(CRC) for improved audio quality.		(CRC) for improved audio quality.
	The MPEG audio data is binary data, and must be encoded for		The MPEG audio data is binary data, and must be encoded for
	non-binary transport; the Base64 encoding is suitable for Email.		non-binary transport; the Base64 encoding is suitable for Email.
	Note that the MPEG audio data does not compress easily using		Note that the MPEG audio data does not compress easily using
	lossless compression.		lossless compression.
	Security considerations:		Security considerations:
	Data concatenated with the MPEG stream might contain executable		MPEG is a tagged data format, and some tags are available for
	code. This executable code can only be executed by a program that		private use. As such, arbitrary material could potentially
	looks for it and is not executed by an MPEG audio decoder when it		be transferred in the MPEG stream, including executable content.
	attempts to play the file. It's simply ignored.		Tagged data containing executable content SHOULD never be sent
			and MUST not be executed if it is received.
			NOTE
			The requirement that such content not be executed on receipt
			is especially important since situations exist where content
			will be generated independently and therefore could contain
			executable content that the sender is unaware of.
			Audio/mpeg objects are not signed or encrypted internally.
			External security mechanisms must be employed to ensure content
			confidentiality
			Internet DRAFT The audio/mpeg Media Type August 2000
	Interoperability considerations:		Interoperability considerations:
	MPEG audio has proven to be widely interoperable across computer		MPEG audio has proven to be widely interoperable across computer
	platforms.		platforms.
	Published specification: see [MPEG-1] and [MPEG-2]		Published specification: see [MPEG-1] and [MPEG-2]
	Applications which use this media type:		Applications which use this media type:
	MPEG audio is device-, platform- and vendor-neutral and is		MPEG audio is device-, platform- and vendor-neutral and is
	supported by a wide range of encoders and decoders (players).		supported by a wide range of encoders and decoders (players).
	Additional information:		Additional information:
	Magic number(s): none		Magic number(s): none
	File extension(s): .mp1, .mp2, .mp3		File extension(s): .mp1, .mp2, .mp3
	Macintosh File Type Code(s): MPEG		Macintosh File Type Code(s): MPEG
	skipping to change at page 3, line 27 ¶		skipping to change at page 3, line 37 ¶
	The author of this draft.		The author of this draft.
	Intended usage: COMMON		Intended usage: COMMON
	Author/Change controller: Martin Nilsson (see section 5)		Author/Change controller: Martin Nilsson (see section 5)
	3. References		3. References
	[ID3v2]		[ID3v2]
	Martin Nilsson, "ID3v2 informal standard".		Martin Nilsson, "ID3 tag version 2.3.0".
	<url:http://www.id3.org/id3v2-00.txt>		<url:http://www.id3.org/id3v2.3.0.txt>
	[MPEG-1]		[MPEG-1]
	ISO/IEC 11172-3:1993.		ISO/IEC 11172-3:1993.
	Coding of moving pictures and associated audio for digital storage		Coding of moving pictures and associated audio for digital storage
	media at up to about 1,5 Mbit/s, Part 3: Audio.		media at up to about 1,5 Mbit/s, Part 3: Audio.
	Technical committee / subcommittee: JTC 1 / SC 29		Technical committee / subcommittee: JTC 1 / SC 29
	[MPEG-2]		[MPEG-2]
	ISO/IEC 13818-3:1995		ISO/IEC 13818-3:1995
	Generic coding of moving pictures and associated audio information,		Generic coding of moving pictures and associated audio information,
	Part 3: Audio.		Part 3: Audio.
	Technical committee / subcommittee: JTC 1 / SC 29		Technical committee / subcommittee: JTC 1 / SC 29
	and		and
	ISO/IEC DIS 13818-3		ISO/IEC DIS 13818-3
	Generic coding of moving pictures and associated audio information,		Generic coding of moving pictures and associated audio information,
	Part 3: Audio (Revision of ISO/IEC 13818-3:1995)		Part 3: Audio (Revision of ISO/IEC 13818-3:1995)
			Internet DRAFT The audio/mpeg Media Type August 2000
			[RFC2119]
			S. Bradner, "Key words for use in RFCs to Indicate Requirement
			Levels", RFC 2119, March 1997.
			<url:ftp://ftp.isi.edu/in-notes/rfc2119.txt>
	4. Full Copyright Statement		4. Full Copyright Statement
	Copyright (C) The Internet Society (2000). All Rights Reserved.		Copyright (C) The Internet Society (2000). All Rights Reserved.
	This document and translations of it may be copied and furnished to		This document and translations of it may be copied and furnished to
	others, and derivative works that comment on or otherwise explain it		others, and derivative works that comment on or otherwise explain it
	or assist in its implmentation may be prepared, copied, published and		or assist in its implmentation may be prepared, copied, published and
	distributed, in whole or in part, without restriction of any kind,		distributed, in whole or in part, without restriction of any kind,
	provided that the above copyright notice and this paragraph are		provided that the above copyright notice and this paragraph are
	included on all such copies and derivative works. However, this		included on all such copies and derivative works. However, this
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